Process for the manufacture of foils and sheets of molding compositions of tactic vinyl chloride homo and/or copolymers

ABSTRACT

Molding composition containing tactic vinyl chloride homo or copolymer and 5 to 25 weight percent of at least one member selected from the group consisting of a binary copolymer of methyl methacrylate and 1 to 20 weight percent of another methacrylate or 1 to 10 weight percent of an acrylate each having an alcoholic moiety of two to 10, preferably two to four, carbon atoms; a graft copolymer of methyl methacrylate, butadiene and styrene; and a graft copolymer of acrylonitrile, butadiene and styrene. This molding composition has improved physical properties as compared to tactic vinyl chloride polymers alone.

United States Patent Bierwirth et a1. Sept. 5, 1972 [541 PRocEss FOR THEMANUFACTURE References cited 1 OF FOILS AND SHEETS OF MOLDING ACOMPOSITIONS OF TACTIC VINYL UN D STATES PATENTS CHLORIDE HOMO AND/OR3,373,229 3/1968 Philpot ..260/899 COPOLYMERS 2,943,074 6/1960 Feuer..260/876 9 2,802,809 8/1957 Hayes ..260/876 [721 lnventorsl EgonBlerwlrth; Robe" Bunmg, 3,445,416 5/1969 Condo ..260/876 both ofOberlar; Harald Dorffurt, Hangelar; Hans-Ewald Konermann, FOREIGNPATENTS OR APPLICATIONS Oberlar all of Germany 1,438,017 3/1966 France[73] Assignee: Dynumit Nobel AG, Troisdorf, a Examiner samuel BlechGermany Attorney-Burgess, Dinklage & Sprung 22 Filed: Oct-2, 1969 57ABSTRACT [21] Appl. No.: 863,314 Molding composition containing tacticvinyl chloride homo or copolymer and 5 to 25 weight percent of at leastone member selected from the group consisting [30] Forelgn Apphcat'onPnomy Data of a binary copolymer of methyl methacrylate and 1 to ()m 5,1968 G a y ,P 18 01 400,1 20 weight percent of another methacrylate or 1to 10 4 weight percent of an acrylate each having an alcoholic 52 US.Cl. ..260/876 R, 260/880, 260/897 0, moiety of two to 10, Preferably twoto four, carbon 260/898 260/899 264/176 atoms; a graft copolymer ofmethyl methacrylate, bu- 51 Int. Cl. ..cosr 29/24 tadiene and Styrene;and a graft P Y of 58 Field or seeii ciiu ..260/876 899 acrylmitrileebutadiene and styrene- This mdding composition has improved physicalproperties as compared to tactic vinyl chloride polymers alone.

9 Claims, N0 Drawings PROCESS FOR THE MANUFACTURE OF FOILS AND SHEETS OFMOLDING COMPOSITIONS OF TACTIC VINYL CHLORIDE HOMO AND/OR COPOLYMERS Itis in the prior art to manufacture film, foils or sheets of atactic,plasticizer-free vinyl chloride polymer molding compositions usingcalendering or extrusion methods. The term atactic polyvinyl chloride inthis case refers to a vinyl chloride polymer which has been made bypolymerization, preferably at 50 C., with peroxides and exhibitssubstantially no steric arrangement of the chlorine atoms thereof. Theopposite of this is tactic polyvinyl chloride, which is made by specialpolymerization processes, such as those described in British Pat. No.855,213, German Auslegeschrift No. 1,111,826 and French Pat. Nos.1,230,844, 1,259,267 and especially 1,438,017, is characterized in thatit exhibits a particular given steric order tacticity) of the chlorineatoms. The difficulties that are to be expected in the working of atactic polyvinyl chloride are described by O. C. Bockmann in BritishPlastics, June 1965, page 364-365, in his article StereoregularCrystalline PVC. The reason for the difficulties in working thismaterial in comparison to working atactic polyvinyl chloride is thehigher melting temperature of this material, which is 20 to 30C. higherthan the melting range of another wise similar atactic polyvinylchloride, depending on the degree of regularity tacticity) of thearrangement of the chlorine atoms. The correlatively higher workingtemperatures necessary for formation result in a relatively highdecomposition ratio of tactic polyvinyl chloride upon molding since thedifference between the thermostabilities of tactic and atactic polyvinylchloride is not sufficiently great to take care of this requiredincreased temperature.

Since increasing efforts are being made to reduce the workingtemperatures required for the working of atactic polyvinyl chloride, asfor example by the preparation of suitable copolymers, etc., it becomesall the more necessary to accomplish the same thing for the working oftactic polyvinyl chloride. In most cases, however, better workabilitycan be achieved only at a loss of other characteristics, such aslowering of the Vicat temperature, which represents an index of thermalstability of shape H. Houwink, Chemie and Technologie der Kunststoffe,Vol. 1, 3rd ed. (1954), p. 652). Attempts to use butadiene copolymers orchlorinated polyethylenes as working adjuvants and elasticizing agentshave proven unsuccessful, as it appears from German Auslegeschrift No.1,208,882, because not only does this make the tactic polyvinyl chloridemore brittle, but it also produces an undesired lowering of the Vicattemperature. In order to maintain the high Vicat temperature of tacticpolyvinyl chloride, the last above mentioned German Auslegeschriftsuggests the admixture of postchlorinated polyvinyl chloride with tacticpolyvinyl chloride. Mixtures containing post chlorinated polyvinylchloride, however, in spite of having physiologically acceptablestabilization, have the disadvantage of unsatisfactory thermostability.Materials of this sort therefore often decompose when they are beingrolled out on a calender. Another disadvantage of such material is itspoor ductility in the warm state. This disadvantage is most notable inthe deep drawing of film or sheeting made of tactic polyvinyl chlorideaccording to methods known hitherto.

Surprisingly, it has now been found that all of the above-mentioneddisadvantages, such as poor elasticity, poor workability due topremature decomposition, embrittlement, lowering of the Vicattemperature, and poor deep drawing qualities of film and sheeting can beavoided by utilizing as molding compositions a mixture of tactic vinylchloride polymers and up to 25 weight percent of a. A binary copolymerof 1) methyl methacrylate and (2) 1-20 weight percent of at least oneother methacrylic acid ester or 1 -10 weight percent acrylic acid esterwhich esters have alcohol components containing two to 10 carbon atoms,preferably two to four carbon atoms in straight or branched chainconfiguration and/or b. A graft copolymerizate of methylmethacrylate/butadiene/styrene and/or c. A graft copolymerizate ofacrylonitrile/butadiene/styrene.

If the a) copolymer is used above,.it should constitute about 1-25weight percent of the entire mixture. If the (b) or c) copolymers areused it should constitute about 5 to 25 weight percent of the entire mixture. If combinations of (a), (b) and (c) or any two of them are usedthe collective proportions should be about 1 to 25 weight percent of theentire mixture.

It is desirable to use a tactic vinyl chloride polymer or copolymerwhich has been polymerized or copolymerized in the known manner atconversions of greater than '30 percent known catalysts at temperaturesbetween 0C. and C., preferably between -5 C. and 20C., under shearingconditions such as for example in cylindrical vessels containingrotating grinding bodies or in vessels having agitators with a shearingaction (cf. French Pat. No. 1,438,017).

Tactic copolymers of the vinyl chloride usually have as comonomers: l,Z-trans-dichloroethylene, trichloroethylene, tetrachloroethylene,vinylacetate, vinylpropionate, vinylethers, acrylonitrile, acrylic acidesters or methacrylic acid esters, ethylene and/or propylene. Thecomonome'rs usually constitute about 0.5 to 10 weight percent of thecopolymer.

In the manufacture of molding compositions it is expeditious to mix thecomponents at l185C. on a heated kneading masticating) unit, such as atwo-roll mill or an extruder; plasticize the molding compositions; androll these compositions, via a calendar into film or sheeting. In thealternative, the molding compositions may be extruded into films orsheets through a slot die extrud er using as the maximum temperature ofthe molding compositions in the slot die to 205C.

The following compositions are especially suitable for use in admixturewith tactic vinyl chloride polymers to produce the improved moldingcompositions of this invention:

1. Polymerizates which were produced by copolymerizing methylmethacrylate with at least onev other methacrylate, the alcoholcomponents of which contain two to 10, preferably two to four, carbonatoms, whereby 99-80 weight percent of methyl methacrylate and l-20weight percent of the C -C ester, preferably C C -ester, of themethacrylic acid are present in the final copolymer.

2. Polymerizates which were produced by copolymerizing methylmethacrylate with esters of the acrylic acid, the alcohol components ofwhich contain two to 10, preferably two to four, C-atoms, and whichacrylates constitute 1-10 weight percent of the final copolymer. I

The manufacture of the polyrnerizates mentioned under (1 and (2) can becarried out for instance, in accordance with Houben-Weyl .Methoden derorg. Chemie, Vol XIV/1, Makro-molekulare Stoff" page 1,046.

I 3, Graft copolymerizates of acrylonitrile and styrene on butadienepolymer. The polymer back bone may be copolymerizates ofacrylonitrile/styrene and/or but'adiene/acrylonitrile or mixtures of allthese; The produce contains copolymerized butadiene in a proportionv of5-10 weight percent acrylonitn'le in a proportion of 15-35 weightpercent and styrene in a proportion of 45-80 weight percent.

The manufacture of these graft copolymerizates can be carried out,for'instance, in accordance with the following literature: Belgian Pat.Nos. 651,066, 665,901, 671,228 and 671,229. British Pat. Nos. 1,001,437,French Pat. No- 1,430,214, Houben-Weyl, Methoden der org. Chemie, Vol.XIV/1, Makromolekulare Stoffe, pp. 396-400.

4. Graft copolymerizates of methyl methacrylate and styrene onbutadiene-polymer. The polymer back bone may be copolymerizates ofmethacrylic acid ester/styrene and/or butadiene/methacrylic acid esteror mixtures of all these. The product contains copolymerized .butadienein an amount of 5-30 weight percent methyl methacrylate in an amount of35-60 weight percent and styrene in an amount of -40 weight percent.

The manufacture of these graft copolymerizates can, for instance, becarried out in accordance with the following-patents:

Belgian Pat. Nos. 671,228 and 671,229

British Pat Nos. 963,372 and 1,001,437 The compositions set forth under1-4 above'are each combined with tactic polyvinylchloride in a suitablemanner. Known stabilizers for the manufacture of PVC-molding.compositions, lubricants and/or fillers etc., may be added for theirusual intended purpose in their normal amounts, for example forimproving the workability of the tactic polyvinyl chloride.

The molding material is then preplastified at 175-18 5C. on a two-rollmill or another heated kneading means, such as an extruder and rolled(extruded) as a hot mass:

' a. to a calender and rolled to a filmat the calender roll temperatureslisted in Table l, or

b. after plastification in an extrudenthey are driven through a slot orcircular die extruder, at a temperature ranging between 195 and 205C toform film or sheetv plastification. This diminished strength manifestsitself, for example, in frequent cracking of these films or sheets atthe lateral margins thereof under the tension applied in pulling themfrom the calender. On the other hand, if higher working temperatures areused, the same molding composition decomposes, so that a technicallyusable product is not obtained in this .way, either. l

The molding compositions according to the invention, based on tacticpolyvinyl chloride can nevertheless be worked like ordinary moldingcompositions based on atactic polyvinyl chloride. The films or sheetsmanufactured from the molding compositions according to the inventiondisplay not only the generally known desirable properties of a polyvinylchloride film form material but also a thermal stability of shape (Vicattemperature) that is 12 to 15C. higher. The films or sheeting'preparedfrom the molding composition of the invention can furthermore be deepdrawn in an outstandingmanner with the application of heat.

The drawn articles thus obtained can be used for the packaging ofproducts as hot as 85C. such as those encountered in pasteurizingprocesses in the food industry. Containers made from atactic polyvinylchloride, such as deep drawn drinking cups, cannot withstandtemperatures beyond to 72C. under the same conditions.

The following examples are given by way of illustration of thisinvention without being limiting thereon.

EXAMPLE 1 10.0 Kg. of tactic polyvinyl chloride containing 68 percent ofsyndiotactically arranged chlorine atoms, which is either used as a:

a. homopolymer; or V b. copolymer with 5 weight per cent of 1,2-trans- Vdichloroethylene whereby the K value amounts to 62 in each case. The.

tacticity was determined in accordance with the following literature: H.Gerrnar, K. H. l-lellwege, U. Johnsen, Makromolekulare Chemie, Vol. 60(1963), pp. 106-119. 0.2 Kg. of stabilizer composed of 75 weight percentof a di-n-octyl-tin-sulphur-compound and 25 weight percent epoxidizedsoybean oil, commercial name Advastab 17 MO of the firm Deutsche AdvanceGmbH and 0.1 Kg of a montanic acid ester such as OP-Wach (Commercialname of Farbwerke Hoechst) as lubricant, are mixed together for 10minutes at 20C. in a fluid mixer. The compound is plastified for 6minutes at 212C. on a two-roll mill, and then the hot mass is rollmolded into a film on a fourroll calender at the following temperatures:first roll 212,C., second roll 215C., third roll 218,C., fourth roll222C, measured in the direction of movement of the film. I

EXAMPLE 2 The mixture described in Example 1, using a tactic vinylchloride copolymer formed with 5 weight percent oftrans-dichloroethylene is mixed as described in Example l with theaddition of 0.4 kg of a copolymer of weight percent of methylmethacrylate and 15 weight percent of vbutyl methacrylate and is workedinto a film at the temperature stated in Table 1 EXAMPLE 3 'The mixturedescribed in Example 1, using a tactic vinyl chloride copolymer formedwith 5 weight percent of transdichloroethylene and with the addition of0.4 kg of a copolymer consisting of 95 weight percent of methylmethacrylate and 5 weight percent of ethyl acrylate is worked into afilm at the temperatures stated in Table 1.

EXAMPLE 4 The mixture described in Example 1, using a tactic I vinylchloride-copolymer formed with 5 weight percent of transdichloroethyleneand with the addition of 0.8 kg of a graft copolymer of methylmethacrylate/butadiene/styrene with a grafted methyl methacrylateportion of 49 weight per cent and a styrene-portion of 22 weight percent(the commercial product Paroloid KM 228 of the firm Rohm & Haas,Philadelphia, U.S.A. can also be used), is mixed analogous to Example land is worked into a film at the temperature stated in Table 1.

EXAMPLE 5 The mixture described in Example 1, using a tactic vinylchloride-copolymer with 5 weight percent of trans-dichloroethylene withthe addition of 0.8 kg of a graft copolymer ofacrylonitrile/butadiene/styrene with an acrylonitrile content of 24weight percent and a styrene content of 61 weight percent is plastifiedunder the conditions stated in Table l and rolled into a film.

EXAMPLE 6 The mixture described in Example 1 using a tactic vinylhomopolymer and with the addition of 0.4 kg of a copolymer consisting ofweight percent of methyl methacrylate and 5 weight percent of ethylacrylate is worked into a film under the conditions stated in Table 1.

EXAMPLE 7 The mixture described in Example 1, using a tactic vinylchloride-copolymer with 5 weight percent of trans-dichloroethylene andwith the addition of 0.3 kg of a copolymer consisting of 95 weightpercent of methyl methacrylate and 5 weight percent of ethyl acrylateand 0.4 kg of an acrylonitrile/butadiene/s tyrene-graft copolymeraccording to Example 5 is worked into films under the conditions statedin Table 1.

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Drinking cups were prepared by deep drawing of films (0.4 mm thickness)made of the various tactic polyvinyl chloride compositions having thefollowing dimensions: Diameter at brim 7 cm, diameter at bottom cm,height 7 cm. These cups were supported by a ring clamp at the top edgeand thus, with the bottom suspended in the air, filled with hot water atdifferent temperatures. The maximum temperature at which no bulging ofthe bottom occurred was noted.

By the calender process, films can be made in thicknesses of 0.08-0.6mm, and using a slot die extrusion process films can be made havingthicknesses of 0.6 to 1 mm, and sheets having thicknesses up to, forexample 10 mm.

What is claimed is:

1. A polyvinyl chloride composition suitable for use as a film or sheetforming molding material comprising tactic vinyl chloride polymerprepared by catalytic polymerization at 0 to 60C in a rotatingpolymerization zone under shearing conditions at conversions of morethan 30 percent and an effective amount up to out 25 weight percent ofat least one additive selected from the group consisting of:

a. a binary copolymer of methyl methacrylate and a different esterselected from the group consisting of 1 to weight percent of amethacrylate or 1 to 10 weight percent of an acrylate, wherein thealcoholic moiety of said different ester contains about two to 10 carbonatoms;

b. a graft copolymer of 35 to 60 weight percent methyl methacrylate/S to30 weight percent butadiene/ 10 to 40 weight percent styrene; and

c. a graft copolymer of l5 to 30 weight percent acrylonitrile/S to 10weight percent butadiene/4S to weight percent styrene.

2. A composition as claimed in claim 1 wherein said alcoholic moiety hastwo to four carbon atoms.

3 A film of the compositions claimed in claim 1.

4. A composition as claimed in claim 1 having 1 to 25 weight percent ofadditive a).

5. A composition as claimed in claim 1 having 5 to 25 weight percent ofthe additive (b) and/or (c).

6. A composition as claimed in claim 1 wherein said tactic vinylchloride polymer is a homopolymer.

7. A composition as claimed in claim 1 wherein said tactic vinylchloride polymer is a copolymer with at least one comonomer selectedfrom the group consisting of 1,2-trans-dichloroethylene,trichloroethylene, tetrachloro ethylene, vinyl acetate, vinylpropionate, a vinyl ether, acrylonitrile, an acrylate, a methacrylate,ethylene and propylene.

8. A composition as claimed in claim 7 wherein said comonomer is presentin a proportion of about 0.5 to 10 weight percent of said vinyl chloridepolymer.

9. A composition as claimed in claim 1 wherein said tactic vinylchloride polymer has 'a syndiotacticity of the chlorine thereof of about68 percent.

2. A composition as claimed in claim 1 wherein said alcoholic moiety hastwo to four carbon atoms. 3 A film of the compositions claimed inclaim
 1. 4. A composition as claimed in claim 1 having 1 to 25 weightpercent of additive a).
 5. A composition as claimed in claim 1 having 5to 25 weight percent of the additive (b) and/or (c).
 6. A composition asclaimed in claim 1 wherein said tactic vinyl chloride polymer is ahomopolymer.
 7. A composition as claimed in claim 1 wherein said tacticvinyl chloride polymer is a copolymer with at least one comonomerselected from the group consisting of 1,2-trans-dichloroethylene,trichloroethylene, tetrachloro ethylene, vinyl acetate, vinylpropionate, a vinyl ether, acrylonitrile, an acrylate, a methacrylate,ethylene and propylene.
 8. A composition as claimed in claim 7 whereinsaid comonomer is present in a proportion of about 0.5 to 10 weightpercent of said vinyl chloride polymer.
 9. A composition as claimed inclaim 1 wherein said tactic vinyl chloride polymer has a syndiotacticityof the chlorine thereof of about 68 percent.